Needle-bar drive for zig-zag sewing machines



Dec. 15, 1953 F. PARRY 2,662,495

NEEDLE-BAR DRIVE FOR ZIG-ZAG SEWING MACHINES Filed Oct. 5, 1950 3 Sheets-Sheet l ED Zjmawtov ?rank @rlz'y 2% Q WW .JWK

@kbmmg Dec. 15, 1953 F. PARRY 2,662,45 Q

NEEDLE-BAR DRIVE FOR ZIG-ZAG SEWING MACHINES Filed Oct. 5, 1950 3 Sheets-Sheei 3 W Llm/aay Swen/tow Ellckoznaxy UNITED STATES PATENT QFFICE NEEDLE-BAR DRIVE FOR ZIG-ZAG SEWING MACHINES Frank Parry, Trumbull, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application October 5, 1950, Serial No. 188,502 9 Claims. (01. 112158) 2 This invention relates to sewing machines and Fig, 6 is a enlar ed iew of the needle and more particularly to an improvement in the loop-seizing beak ofthe loop-taker, showing, in eedle-bar drive of a sewi machine h g a full lines, the relative position or" the needle and vibratory needle-bar; an example of such a maloop-seizing beak at one penetration of the chine being one designed to sew zigzag stitches. needle and, in dotted lines, the relative position The principal object of the present invention of the needle and the loop-seizing beak on the is to provide an improved driving connection for alternate penetration of the needle.

transmitting endwise reciprocation to the needle- In the sewing machine illustrated in the drawbar while permitting vibratory motion of the ings, the needle-bar is adapted to be endwise reneedle-bar inalateral direction. m ciprocated in a needle-bar frame which is piv- Another object of the present invention is to otally supported within the sewing machine head provide, in a sewing machine, an improved drivso that it can be vibrated in a direction across ing connection between the rotary arm-shaft the normal line of feed in a vertical plane parand the endwise reciprocatory and laterally allel to the vertical plane of rotation of the covibratory needle-bar, which connection is simple I operating horizontal-axis loop-taker. The endin design and has incorporated in it a commer- Wise reciprocation of the needle-bar coupled with cial antifriction bearing which contributes to the vibratory movement of the needle-bar frame the elimination of any binding action occuring requires a needle-bar drive having capacity for in the needle-bar drive. 0 universal movement between the needle-bar and Still another object of the present invention the needle-bar actuating crank fast on the rotary is to provide an improved and simplified drive arm-shaft. Also, for relatively wide needle-vifor a vibratory needle-bar which efiects a deeper bration, it is preferable that the needle-bar drive penetration of the needle on alternate thrusts be such as automatically to compensate for the of the needle-bar for the purpose of establishlateral shift of the needle relative to the axis of ing the proper timing relation between the rotation of the loop-taker in order that the thread-loop cast out by the needle and the adthread-loop cast out by the ascending needle will vancing loop-seizing beak of the loop-taker. be unerringly seized by the loop-taker regard- Other objects and advantages of the present less of the position of penetration of the needle. invention will appear from the detailed descrip- Referring to the drawings, the sewing machine tion of an illustrative form of the same, which 3U illustrated has a frame including a bed ID from will now be given in conjunction with the acone end of which rises a standard ll merging companying drawings, in which: at its upper end in a bracket-arm l2 which ter- Fig. 1 is a front elevational view of a lockminates at its free end in a hollow head I 3. R0- stitch zigzag sewing machine embodying one ly i r l d in b lr n s M n h form of the present invention, a portion of the bracket-arm is a rotary actuating" needlebracket-arm being sectioned to illustrate the delecipmcating ft 5 eXtendiIlg horizontally tails of the mechanism within said bracket-arm. lengthwise f th ra trm l nd arryin Fig 2 i an enlarged m; end view of th at its exposed end a belt-driven balance-wheel sewing machine t t face p1a,te and large It. Journaled in suitable bearings provided in needle-thread take-up k removed, and t the bed I0 is a rotary bed-shaft 11 connected to a portion of the bed sectioned to illustrate the be driven by a bolt i from th actuating armfeed..dog shaft [5. At the head-end of the machine, the

Fig. 3 is a horizontal sectional view of the mabed-Shaft is connected through gears and chine-head taken substantially along the line 20 to horizontally disposed ta y loop-taker 3 3 Fig 2 shaft 2i journaled in a suitable saddle 22 de- Fig'. 4 is an enlarged view of the needle-bar pending from the bed I0. Carried on the loopcrank-pin with a portion of the counterbalance taker shaft 2| 1S a loop-Faker 23 preferably of and the upper end of the needle-bar link secthe rotary: hook f havmg a loop-seizing beak 5 is a front elevational iew e tion of transverse to the IlOrmal direction of feed of the a lock-stitch zigzag sewing machine embodying Work determined by the usual g 25 and a modification of the needle-bar drive illustrated Opposed p ng-depressed D root 26. in Fig. 1, the needle-bar driving link in this figure mpl ment l to the loop-taker n the formabeing shown as positioned outside the vibratory tion of lock-stitches is a thread-carrying needle needle-bar frame. 21 carried in the lower end of a needle-bar 28 journaled for endwise reciprocation in the spaced bearings 29 and 30 of a vibratory needle-bar frame 3|. As shown in Figs. 2 and 3, the vibratory frame 3| is supported to pivot on a pair of alined pintles 32 fixed in the front and rear walls of the machine head l3. The pintles 32 extend into hardened inserts 33 pressed into the vibratory frame 3| which is preferably made of lightweight metal.

To effect vibration of the frame 3 i, it has connected to its upper end the outer end of a pitman 34 embracing at its inner end a conventional form of adjustable eccentric 35 mounted on a crossshaft 36 driven by gears 31, 33 from the armshaft [5 at a speed equal to one-half that of the arm-shaft. From the above, it will be understood that rotation of the arm-shaft l5 will effect rotation of the crossshaft 33 at one-half the speed of the arm-shaft and, through the eccentric 35 and pitman 36, the frame 3! is caused to vibrate on its pintles 32 in a direction to shift the needlebar 28 crosswise of the seam line, thereby to produce zigzag stitches.

Simultaneously with the vibration of the frame 31, the needle-bar 23 is adapted to be endwise reciprocated in the spaced bearings 29 and 30 of the frame 3!. This is accomplished by means comprising a pivot-stud 39 clamped upon the needle-bar 28 and slidably carrying a spherically surfaced element or ball-member 4O embraced by the spherically seated lower end of a needle-bar linkAl. At its upper end, the needle-bar link is bored to receive a commercial needle-bearing 42, the cylindrical needles of which engage the crowned or spherical surface 33 of a needle-bar actuating crank-pin 44 fastened in the usual counterbalanced needle-bar actuating crank 45 secured on the arm-shaft l5. To prevent the needle-bar 28 fromturning in its bearings 29 and 33, and likewise to prevent the link M from turning on the crank-pin 44, the pivot-stud 39 is extended and the needle-bar link 4!, at its lower end, is formed with a projection 43 internally bored to snugly embrace the horizontally opposite sides of the extended pivot-stud 39 and externally sized to slidably engage the sides of a vertically disposed guideway l'l formed in the guide-block 48 attached by screws 49 (Fig. 3) to a seat 59 milled in the head 13.

From the foregoing, it will be understood that the ball-and-socket connection at the lower end of the needle-bar actuating link M together with the crowned surface 43 of the needle-bar crankpin M, permits the needle-bar link 4| limited universal movement so that the needle-bar 28, through the frame 3!, can be vibrated transversely of the normal line of feed, without in any way binding or cramping the needle-bar or its driving connection. Moreover, the crowned portion 43 on the needle-bar crank-pin is a simple and effective way of obtaining a universal connection between the crank-pin M and the link 4!, and particularly since it lends itself to the use in combination with a commercial form of antifriction needle-bearing 42. One of the advantages of using a needle-bearing in this location is that little lubrication is needed to effectively lubricate it. The requirement of only a small amount of lubricating oil for this connection reduces to a minimum the danger of excess oil collecting in the bottom of the head l3, and consequent soiling of the work being stitched.

Figs. 5 and 6 illustrate a modification of the sewing machine shown in Figs. 1 to 4. The modification relates to the needle-bar reciprocating means and more specifically to the location of the needle-bar actuating link M with respect to the needle-bar 28 and its vibratory frame 3|. The purpose of this relocation of the needle-bar actuating link GI is to provide a better timing between the needle 21 and the loop-taker 23 at the opposite ends of needle vibration. It will be understood that since the needle vibrates in a vertical plane disposed crosswise of the line of feed and the plane of rotation of the horizontal axis looptaker is disposed parallel to this plane, it follows that when the needle is vibrated inwardly toward the standard (full lines, Fig. 6) and the loop-taker is rotating in a counterclockwise direction as viewed from the front of the machine, the hook-beak 24 will pass the eye of the needle earlier in point of time than when the needle is in neutral position. Likewise, when the needle is vibrated outwardly away from the standard (dotted lines, Fig. 6), the hook will pass the eye of the needle later than when in neutral position. The needle-bar actuating mechanism disclosed in Fig. 5 compensates for this difference in timing by causing the needle 21 to descend to a lower position when it is vibrated outwardly than when vibrated inwardly. To that end, the counterbalanced crank s5 is formed with an outwardly extending projection 31 bored to receive the crank-pin 44 having the crowned surface 43 formed adjacent its outer end. Embracing the crowned surface 23 is the antifriction needlebearing 42 carried in the upper end of the needlebar link 4|. The lower end of the needle-bar link is spherically socketed to receive the ballelement 49 mounted on the pivot-stud 39 clamped on the needle-bar 28. It will be seen in Fig. 5 that the needle-bar link 4| is arranged on the outside of the needle-bar 28 instead of on the inside, as is the case in the mechanism shown in Fig. l. The pivot-stud S9, in this modification, is disposed to project outwardly with its free end arranged to slide in a guideway 52 formed in a block 53 suitably fastened to a cover-plate 54 which'is attached to the front of the machine head.

From the above, it will be understood that the change of timing of needle-reciprocation at the opposite ends of the vibratory movements of the needle is a result of a small amount of needle-bar reciprocation caused by oscillation of the vibratory frame. Inasmuch as the connection between the needle-bar 28 and the needle-bar link 41 is positive, the angular relation of the pivotstud 39 and the driving link 4i during pivotal movements of the vibratory frame 3| about the axis of the pintles 32 causes this relative slight endwise movement of the needle-bar in the vibratory frame. When the driving link is disposed outside the vibratory frame or, in other words, when the link is disposed on that side of the axis of vibration of the needle opposite to that of the approach to the needle of the loop-taker beak 24, in the manner shown in Fig. 5, the needle-bar reciprocations are advanced and retarded to coincide with the late and early positions of the beak of the rotary hook 23. Referring to Fig. 6, it will be seen that on the inside penetration of the needle (full line position), the lowest position of needle dip is indicated by the line a-a and that, in ascending to cast out the usual needle-thread-loop, the needle rises to the point indicated by line b--b, at which point the beak 24 of the loop-taker is in proper position to seize the cast-out needle-thread-loop. On the outside penetration of the needle (dotted line position), the lowest position of needle dip is indicated by the line 0-0 and, in ascending to cast out the needle-thread-loop, the needle rises to the point indicated by the line dd, at which point the loop-taker beak 24' is again in proper position to seize the cast-out needle-thread-loop. It will be readily observed in Fig. 6 that the needle on the outside penetration dips to a lower position than on the inside penetration, the difference in the depths of penetration being indicated by the letter 9:. This difference in depth of needle penetration results from the angular relation of the pivot-stud 39 and the driving link 4] as fully described above. The advantage of the different depths of needle penetration is readily apparent in Fig. 6, because it will be seen that the same relationship between the eye of the needle and the beak of the loop-taker occurs at either inside or outside penetration of the needle. Since this relationship is constant, an accurate timing setting of the needle and the loop-taker can be made, with the assurance that such setting will be identical for either penetration of the needle.

'It will be understood that with the needle-bar link 4| located inside the vibratory frame 3!, l the angular relation of the pivot-stud 39 and the driving link 4| during pivotal movements of the vibratory frame 3|, effects a lesser depth of needle penetration on the outside stroke of the needle than on the inside stroke, and that this aggravates the timing error between the needle and loop-taker.

It will be appreciated that when the supporting pintles 32 are located intermediate the ends of the vibratory frame 3! instead of at its upper extremity, as for example, in the machine disclosed in the U. S. Patent of A. N. Hale, No. 2,310,176, February 2, 1943, the slight endwise movement of the needle-bar resultingfrom the vibration of the frame 31 is increased. This is especially true when the pivot-stud 39 is clamped on the needle-bar in the vicinity of the pivotal axis of the vibratory frame. This being the case, it will be understood that the need for corrective measures is greater in the machine disclosed in the drawings than when the needle-bar frame is pivoted at its upper end. It will be further understood that by arranging the pintles 32 intermediate the ends of the frame 3| and substantially at the center of mass of the frame and needlebar, the inertia forces are reduced and a high speed mechanism results.

Having thus set forth the nature of the invention, what I claim herein is:

1. A sewing machine having a machine-frame including a hollow head provided with a guideway, a rotary actuating shaft journaled in said machine-frame, a vibratory frame mounted within said hollow head, operating connections with said last-named frame for imparting vibratory movements thereto, a needle-bar journaled in said vibratory frame for endwise reciprocation, a pivot-stud secured to said needle-bar, a crankmember secured to said rotary shaft and having a crank-pin provided with a portion formed with a crowned surface, and a link having one of its ends in bearing contact with the crowned surface of said crank-pin and its other end connected to said pivot-stud, said link having a projection disposed in sliding engagement with said guideway in said hollow head to confine said link against turning and having an internal bore sized to embrace snugly the opposite sides of said pivotstud.

2. Needle actuating mechanism for sewing machines, comprising, a rotary actuating shaft, a vibratory frame, operating connections with said frame for imparting vibratory movements thereto, a needle-bar journaled in said frame for endwise reciprocation, a pivot stud secured to said needle-bar, a ball-member slidably mounted on said pivot-stud, a crank-member secured to said rotary actuating shaft and having a crank-pin provided with a portion formed with a crowned surface, a link having one end socketed to embrace said ball-member on said pivot-stud, and an antifriction bearing carried in the other end of said link and including a plurality of rollers disposed to engage the crowned surface of said crank-pin.

3. A sewing machine having a machine-frame including a standard, bracket-arm and hollow head, a rotary actuating shaft journaled in said bracket-arm and extending into said head, a circularly moving loop-taker having a loop-seizing beak movable in a vertical plane, a vibratory frame, operating connections for imparting vibratory movements to said last-named frame in a plane parallel to the vertical plane of movement of said loop-seizing beak, a needlebar journaled in said vibratory frame for endwise reciprocation, a crank-member secured to said rotary actuating shaft, and a needle-bar actuating link connected at one end to said needle-bar and its other end to said crankmember, said needle-bar actuating link being located on that side of said vibratory fram remote from said machine-standard.

4. In a zigzag sewing machine, a machineframe including a standard, bracket-arm and hollow head, a work-feeding mechanism, a rotary actuating shaft journaled in said bracketarm and extending into said head, a circularly moving loop-taker having a loop-seizing beak movable in a vertical plane arranged transversely of the normal direction of feed, a vibratory frame, actuating connections for imparting vibratory movements to said last-named frame in a plane parallel to th vertical plane of movement of said loop-seizing beak, a needle-bar journaled in said vibratory frame for endwise reciprocation, a needle carried by said needle-bar, a crankmember secured to said rotary actuating shaft, and a needle-bar actuating link connected at one end to said needle-bar and at its other end to said crank-member, said needle-bar actuating link being located on that side of the needle remote from said standard of the sewing machine.

5. In a zigzag sewing machine, a machineframe, work-feeding mechanism, a rotary actuating shaft journalecl in said machine-frame, a rotary loop-taker having a loop-seizing beak movable in a vertical plane arranged transversely of the normal direction of feed, a vibratory frame, actuating connections for imparting vibratory movements to said last-named frame in a plane parallel to the vertical plan of movement of said loop-seizing beak, a needle-bar journaled in said vibratory frame for endwise reciprocation, a needle carried by said needle-bar, a crankmember secured to said rotary actuating shaft, and a needle-bar actuating link connected at one end to said needle-bar and at its other end to said crank-member, said needle-bar actuating link being located on that side of the needle-bar opposite to that of the approach of the loopseizing beak to the needle.

6. In a zigzag sewing machine, a machineframe, work-feeding mechanism, a rotary actuating shaft journaled in said machine-frame, a

I rotary loop-taker movable in a vertical plane arranged transversely of the normal direction of feed, a vibratory frame supported to swing on a fixed pivotal axis, actuating connections for imparting vibratory movements to said lastnamed frame in a plane parallel to the vertical plane of movement of said loop-seizing beak, a needle-bar journaled in said vibratory frame for endwise reciprocation, a needle carried by said needle-bar, a crank-member secured to said rotary actuating shaft, and a needle-bar actuating link connected at one end to said needle-bar and at its other end to said crank-member, said needle-bar actuating link being located on the side of the pivotal axis of vibration of said frame opposite to the side of the needle approached by the beak of the loop-taker.

7. In a zigzag sewing machine, a machineframe, work-feeding mechanism, a rotary actuating shaft journaled in said machine-frame,

a rotary loop-taker movable in a vertical plane arranged transversely of the normal direction of feed, a vibratory frame supported to swing on a fixed pivotal axis d1sposed intermediate the ends'of said vibratory frame, actuating connections for imparting vibratory movements to said last-named frame in a plane parallel to the vertical plane of movement of said loop-seizing beak, said actuating connections being connected to said vibratory frame at a point above its pivotal a rotary actuating shaft journaled in said ma;- chine-frame, a vibratory needle-bar frame, operative connections for imparting lateral vibratory movements to said needle-bar frame, a needle-bar journaled in said vibratory frame for endwise reciprocation, a needle carried by said needle-bar, a circularly moving loop-taker complemental to said needle in the formation of stitches and having a needle-thread loop seizing beak, a crank-member carried by said rotary actuating shaft, and a needle-bar reciprocating link connected at one end to said needle-bar and at its other end to said crank member,said needlebar reciprocating link being disposed at the side of said needle-bar opposit to that of the approach of the loop-seizing beak to the needle.

9. A sewing machine having a machine-frame including a standard, a rotary actuating shaft journaled in said machine-frame, a vibratory needle-bar frame, operative connections for imparting lateral vibratory movements to said needle-bar frame, a needle-bar journaled in said vibratory frame for endwise reciprocation, a needle carried by said needle-bar, a circularly moving loop-taker complemental to said needle in the formation of stitches and having a needlethread loop-seizing beak, a crank-member carried by said rotary actuating shaft, and a needlebar reciprocating link connected at one end to said needle-bar and at its other end to said crankmember, said needle-bar actuating linkbeing located on that side of said needle-bar remote from said machine-standard.

FRANK PARRY.

References Cited in the file of this patent UNITED, STATES. PATENTS Number Name Date 7 1,584,697 Bernhard May 11, 1926 1,899,189 Fink Feb. 28,1933 2,308,707 Myers Jan. 19, 1943 2,329,160

' Hale Sept. 7, 1943 

